Leak at fuel sender, replace tank?

Usually when the rubber o ring leaks at the sender, it is because the little tits on the locking ring have lost their spring. All that usually needs to be done is remove the locking ring, remove the gasket, clean it up good and the surfaces where it seals. Then look at the little tits on the locking ring and gently bend them so that the ring will lock back down tighter when you reinstall it. It is very obvious which way you need to bent them when you have it all apart. In 100% of the sender leaks I have encountered thus far, this has fixed them ALL.